From the April 22, 1933, issue
SPARKING PROCESS STUDIED WITH LICHTENBERG FIGURES
What is an electric spark made of, is the question partly answered by the brilliant whirligig figure on the front cover of this week’s Science News Letter. The picture is one of several hundred made during research of Prof. C. Edward Magnusson of the University of Washington, Seattle. Prof. Magnusson’s studies are yielding valuable information on the mechanism of the electric sparkover process.
Engineers studying the effect of lightning on high voltage transmission lines use such designs as that on the cover, known as Lichtenberg figures, to estimate the voltage of tremendous discharges caused by lightning. With a special set-up, they take a picture of the discharge on an ordinary photographic emulsion and the result is a Lichtenberg figure.
At the University of Washington, the same procedure was carried out on a smaller scale in the laboratory. Instead of making the discharge in open air, Prof. Magnusson enclosed his apparatus in an airtight envelope connected to a vacuum pump and photographed figures at very low pressures. He also studied discharges in a magnetic field.
The picture on the cover is one of the most striking taken. The dot at the top represents the positive terminal pressed against the photographic plate, and the bottom dot, actually about three inches away, the negative terminal.
NEW LIGHT-SENSITIVE SUBSTANCE FOUND
A new member of the family of chemical substances that turn dark on exposure to light was announced to the American Chemical Society by Dr. Oskar Baudisch of Yale University and Dr. F.L. Gates of Harvard University.
This is piperidine vanadate. Its crystals change from their original white to black or brown on exposure to light just a little down the wavelength scale from the invisible ultraviolet. The new compound, however, is still so new that practical applications have not yet been suggested.
SCIENTISTS STUDY GOATS THAT BECOME RIGID WHEN EXCITED
Goats so nervous that a shout causes them to become rigid and motionless were described to the members of the American Association of Anatomists.
Drs. Sam L. Clark, Frank H. Luten, and Jessie T. Cutler of Vanderbilt University, Nashville, Tenn., rendered a scientific report on the nervous goats whose peculiar condition is evidently due to an inherited abnormality of the central nervous system.
The goats are so nervously constituted that excitement of any kind makes them perfectly rigid, and they cannot move for a few moments. If they try to run, they fall down and for several minutes cannot bend their legs under themselves in order to get up. The condition is inherited. The rigidity may be brought on by a shout or other noise, by the goat’s losing its balance in trying to climb, or by any kind of excitement.
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